Förster resonance energy transfer (FRET) and applications thereof

FRET is a nonradiative process of energy transfer that is based on the dipole–dipole interactions between molecules that are fluorescent.

Evidence for Free Rotation Restriction of Unsaturated Bond in Aggregation-Induced Emission

We experimentally demonstrate that that nonradiative process, which competes with radiative decay, involves two main stages, namely the restricted intramolecular rotation and internal conversion process. The free rotation restriction of the unsaturated bond at the excited state is the key factor for AIE effects.

Inhibition of the excited-state Rose Bengal (RB) nonradiative process by introducing DMSO for highly efficient photocatalytic hydrogen evolution

The addition of a small amount of DMSO could suppress the deprotonation of excited-state RB nonradiative process caused by proton-induced quenching, which greatly improved the hydrogen evolution performance in RB-sensitized photocatalytic system.

Evidence of a solvent-mediated barrier to radiationless decay in the state of thiophosgene in solution

Thiophosgene, Cl2CS, has been excited in the near-uv and the resulting quantum yields of [Formula: see text] fluorescence and of Cl2CS consumption have been measured as a function of solvent composition (perfluoro-n-hexane, n-hexane, CCl4), temperature, and excitation wavelength. In agreement with previous work it is shown that (i) nonradiative processes dominate the decay of the [Formula: see text] state in solution, and (ii) perfluoroalkane solvents act as inert "heat baths". The process by which the [Formula: see text] state is apparently "quenched" by CCl4 and n-hexane has been discovered. The nonradiative process leading to [Formula: see text] decay involves activation and crossing a barrier, the height of which is a function of the nature and composition of the solvent. CCl4 and n-hexane do not quench the excited state, but instead accelerate its rate of relaxation by lowering the barrier between the bound, radiative portion of the surface and a dark, unbound region. There is evidence that CCl4 or n-hexane form clusters around a Cl2CS solute molecule in mixed perfluoroalkane–CCl4 or n-hexane solutions. Barrier crossing leads to photodecomposition via at least two parallel paths, one free radical (Cl + ClCS) and the other likely molecular (Cl2 + CS), the relative contributions of which are a function of excitation wavelength. Keywords: thiophosgene, photochemistry, solvent-mediated barrier crossing.